Stops don't work in afterhours. And yes, IB does handle their stops in a weird fashion. But once you learn how to deal with it, its manageable. Lets say you want to have a sell stop at 40. Rather than setting that stop at 40, set it at 40.03, if you think the spread on this stock is normally 3 cents. this gets around the IB rule of activating when the ask is the stop, rather than the bid(and vice versa for buy stops). Its not perfect, but it will cut down on slippage.